MHS Blogs

What is a sleep study report actually measuring?

A sleep study report explains how they sleep and how their body functions during sleep, with a particular focus on breathing and oxygen levels. Most reports combine data on brain activity, breathing effort, airflow, oxygen saturation, heart rate, and body movements to provide a comprehensive overview.

Which type of sleep study did they have, and why does it matter?

It matters because HSAT estimates sleep using recording time, while PSG measures sleep directly. That difference can change how indices are calculated and how confident a diagnosis is. HSAT is commonly used when obstructive sleep apnoea is strongly suspected.

What do “sleep stages” and “sleep architecture” mean in the report?

They describe how their sleep is divided across the night, usually into N1, N2, N3 (deep sleep), and REM sleep. A typical report shows time and percentage in each stage, plus a chart (hypnogram) of how stages change. More fragmented sleep often shows as frequent awakenings, lots of light sleep (N1), and reduced deep or REM sleep.

What does “sleep efficiency” tell them?

Sleep efficiency is the percentage of time in bed (or recording time) spent asleep. Lower sleep efficiency usually means more time awake, more awakenings, or difficulty falling asleep. Many labs flag low sleep efficiency because it can worsen daytime tiredness even when breathing indices are mild. It can also reduce REM sleep, which is important because breathing events sometimes cluster in REM.

What are apnoeas, hypopnoeas, and respiratory events?

They are breathing disturbances during sleep that can reduce airflow, oxygen, or cause arousals. An apnoea is typically a near-complete pause in airflow, while a hypopnoea is a partial reduction. Reports may also include RERAs (respiratory effort-related arousals), which are subtler breathing events that fragment sleep. The exact definitions can vary slightly by lab rules, so the report’s scoring criteria matter.